Preservation of cellulose materials



Patented Oct. 29, 1935 PATENT OFFICE I H PRESERVATION OF CELLULOSE MATERIALS Wallace T. Conn, Lawrence, Mass., assignor to the Government of the United States, represented by the Secretary of Commerce No Drawing. Application July 22, 1932, Serial No. 624,139

6 Claims. (CI. 91-68) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 OJG. 757) without the payment to me of any royalty,

thereon.

My invention relates to protecting and preserving cellulose compounds, more particularly to canvas, ropes, cordage, nets, woods, and similar articles which are exposed and subjected to the deteriorating forces of nature.

Cellulose structures, when subjected to the destructive forces of nature, by either constant or intermittent exposures, especially in coastal waters, lakes or rivers, may rapidly deteriorate as a result of the bacteriological, biological, chemical and mechanical action.

The object of my invention is to increase the strength of these materials and to protect such structures from the deteriorating, disintegrating and destructive forces of nature by a simple process of preservation.

I am aware that considerable study of the deterioration of cellulose and fibrous materials has previously been made as is indicated by Harden F. Taylor in Department of Commerce, Bureau of Fisheries Document No. 898. My invention, however, is an improved method of treating such materials and has distinct advantages over that disclosed in prior publications as will be apparent from the detailed description thereof, and further is such a process as can be utilized for treating such materials on a large commercial scale. v

My improved process consists in first cleansing the cellulose material and degumming the same, if it contains an oil, resin or any gummy substance, preparatory to impregnating the same with a toxic dye to provide protection against disintegration, deterioration or destruction by forces other than mechanical. One particular procedure which I have found to be practicable consists in cleansing and degumming the cellulose material by boiling the same for approximately five minutes in an aqueous solution of soap and sodium carbonate, preferably in the ratio of /2 per cent pure white soap and 2 per cent sodium carbonate, and followed by a cold water rinse. in order to cleanse the cellular structure-of for eign and natural repelling forces so that the preservative effect of the toxic dye may be increased by allowing the same to penetrate to the interior of the cellular structures.

After the cellulose material has been degummed, the same is preferably but not neces- I have found this step practicable sarily mordanted. -For textiles, a satisfactory method of mordanting for many dyes consists in exposing the stock in a 2% aqueous solution of tannic acid at F. and then in a 1% aqueous solution of tartar emetic. Certain dyes are quite eflicacious without the use of a mordant and others produce superior effects with a special mordant.

The next stage in the process is the application ofv the dye. m

I have found crystal violet, Color Index Number 681, to be a most efficacious toxic dye, while malachite green, Color Index Number 657 and thioflavine-S, Color Index Number 816 are also of proven value and are very satisfactory as pre- 15 servatives. Satisfactory results have been obtained by using for a given weight of dry cellulose material approximately one per cent by weight of dye dissolved in water, the quantity of water being approximately fifty times the weight of the dry cellulose material. The dyeing operation may be started at sixty degrees Fahrenheit, should be raised to the boiling point and the boiling continued until the cellulose material has remained in the boiling dye for approximately fifteen minutes The stock should then be thoroughly rinsed in cold water and dried. The crystal violet dye produces a purplish colored webbing, malachite green produces a green color and thiofiavine-S produces a yelso lowish color.

The preservative effect of most dyes is increased by an after treatment, the most efilcacious of which for many dyes I have found to be an aqueous solution of approximately 1% potassium bichromate, 2% copper sulphate and 2% acetic acid (30 per cent strength), The dyed stockis exposed in this mixture for 20 minutes at a temperature just below the boiling point. Certain dyes require special fixing-baths 0 or treatments after the dye is applied. All stock should be thoroughly rinsed in cold water as a final operation and then dried. It is recognized that resistance to deterioration of the strength of cellulose structures is provided by certain alcohol soluble dyes which may be applied directly to the cellulose material without preliminary or after treatments, the principle of using a toxic dye as a deterrent to combat the destructive agencies in marine waters being subject to a considerable range in methods of application.

, As a further protection for the treated cellulose material, a cover treatment may be used. One cover treatment which I have found to be satisfactory consists in applying a mixture of appro I and if any one of these treatments is modified or even omitted, the cellulose materialwill still have an increased resistance to deterioration over the untreated material.

experimented, Agerite #10 in the I have found that if cellulose material is degummed then given a suitable mordant treatment followed by a chrome treatment, that the protection is especially efiicacious, particularly with the chrome copper after treatment previously described.

The use of certain anti-oxidants in the tar or the cover treatment has also been foimd to give improved results. The proportion of any specific anti-oxidant is dependent upon its composi-, tion. Y

. Among the anti-oxidants with which I have proportion of in the tar cover of fish net webbing, mateto an oil soluble residual product rially increases the life of the fabric. Agerite No. 10 above mentioned is a. trade name given the composition of which is unknown to the applicant obtained from the distillation of phenyl alpha naphthylamine. The foregoing description comprehends only a general and preferred embodiment of my invention and detail changes in the process, method and compositions may be made withinthescopeo'fthoseclaimswhichmaybe allowed, and therefore these claims are not intendedas restricted to the specific details of my invention as disclosed herein. By experimenting, I have found that the minor details and specific chemicals used may be varied to produce an almost endless number of variations of my invention.

What I claim is:

a 1. An article of manufacture composed of degummed cellulose-fibers containing a toxic dye, a fixer for said dye comprising potassium bichromate, copper sulphate and acetic acid, and a tarlike armoring. I

2. A method for preserving cellulose" material which comprises subjecting said material to a ,degumming process, treating said material with an aqueous solution of tannic acid and tartar emetic and impregnating said treated material with a toxic dye having the bactericidal characteristics of one of the following dyes-crystal violet, malachite green, thiofiavine-S.

3. A method for preserving cellulose material comprising subjecting said material to a degumming process, treating said degummed material with a mordant, ting laid treated material with a toxic dye, applying a dye-fixative solution of potassium bichromate, copper sulphate and acetic acid, and thereafter applying a cover treatment composed substantially of tar.

4. A process for preserving cellulose material 5 which comprises degumming the same with an aqueous solution of soap and sodium carbonate,

mordantin'g the same with an aqueous solution of tannic acid and tartar emetic, dyeing the same with a toxic dye having the bactericidal characteristics of one of the following groupcrysta.l

violet, thiofiavine-S, and malachite green, applying a prwervative treatment having the fixing characteristics of an aqueous solution of potassium bichromate, copper sulphate and acetic acid, and appl ing a cover treatment composed substantially of tar.

5. A process for protecting cellulose material which comprlsesdegumming the material by boiling it for approximately five minutes in an aqueous solution of which approximately is soap and 2% sodium carbonate; rinsing the degummed material in cold water; mordanting the rinsed material in an aqueous solution at approximately 160! F. of which approximately 2% is tannic acid and 1% tartar emetic, dyeing the mordanted'material in an aqueous solution for approximately 15 minutes at approximately boiling tempera ture, thelatter aqueous solution comprising wa-. ter and a. toxic dye having the bactericidal characteristics of crystal violet, thiofiaVine-S, "or malachite green, the quantity of water being approximately 50 times, by weight, of that of the dry mordanted material and the dye being approximately 1%, by weight, of said material, rmsing the dyed material in cold water and thereafter "treating thersame for approximately twenty minutes at approximately boiling temperature in an aqueous solution having the fixing characteristics of approximately 1% potassium bichromate, 40 2% copper sulphate, and 2% acetic acid of 30% strength; rinsing the material thus dyed, and applying a cover treatment comprised substantially of tar for approximately 3 minutes at .a temperature between 180 and 220 IE.

6. A process for protecting cellulose material which comprises degumming the material byan aqueous solution of which approximately ;%is soap and 2% sodium carbonate, mordanting the material in an aqueous solution of which approximately 2% is tannic acid and 1% tartar emetic, dyeing the mordanted-material in an aqueous solution comprising water and a toxic dye having bactericidal characteristicsof crystal violet,

thi'ofiavine-S, 'or malachite green, the quantity of water being approximately 50 times,- by weight,

of that of the dry 'mordanted material andthe dye being approximately 1%, by weight, of said material, thereafter treating the material in an aqueous solution having the fixing characteristics of approximately 1% potassium bichromate,

2% copper sulphate and 2% acetic acid, and applying a cover treatment comprised substantially of tar.

WALLACE 1'. 001m. 

